As the wedding will take place in Beijing, China, the best way to get there is to book a flight.
Beijing Capital International Airport (PEK) is easily reachable from anywhere in the world. You may find daily direct flights or flights with 1 stop from many airports. They usually start around EUR 630.00 from multiple German airports with 1 stop and around EUR 850.00 directly from Frankfurt.
According to Skyscanner.de, the best time to book flights to China is 30 to 50 days in advance.
We have checked on Aug. 1st for 3 weeks later and found the above mentioned prices.